Apparatus for producing variable denier filaments



Jan. 28, 1958 J. s. SENEY 2,820,986

APPARATUS FOR PRODUCING VARIABLE DENIER FILAMENTS Filed Nov. 2'7, 1956 5 Sheets-Sheet 1 III;

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INVENTOR JOHN S. SENEY ATTORNEY J. S. SENEY 3 Sheets-Shegt 2 APPARATUS FOR PRODUCING VARIABLE DENIER FILAMENTS Jan. 28, 1958 Filed Nov. 27, 1956 "kl/31m g I20 n I25 h |2s :l I g l 1 IM I23 'INVENTOR JOHN s. SENEY BY ATTURHEY Jam 28, 1958 J. 5. SENEY 2,820,986

APPARATUS FOR PRODUCING VARIABLE DENIER FILAMENTS Filed Nov. 27, 1956 3 Sheets-Sheet 5 Loiv DENIER 1s DENlER SCALE. 5 0 an 0.

HIGH UENIER I35 INCHES 0F YARN INVENTOR JOHN S. SENEY ATM/HIE? United States Patentl Ofifice 2,320,986 Patented Jar-1: 28, 1958 APPARATUS FOR PRODUCING VARIABLE DENIER FILAMENTS John S. Seney, Seaford, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Application November 27, 1956, Serial No. 624,602

9 Claims. (Cl. 188) This invention relates to a novel apparatus for spinning artificial filaments by extrusion. More particularly, it relates to an apparatus for producing a filament which varies in denier along the filament length, a yarn made from such filaments, and to an apparatus for producing a variable denier multi-filament yarn.

One object of the present invention is to provide an apparatus for changing a steady flow of a liquid to a pulsating flow. Another object is to provide such an apparatus which may be located immediately adjacent the upstream face of a spinneret to form a filament which varies in denier along the filament length. Other objects will become apparent from the descriptions, the drawings, and the claims.

In accordance with the present invention, a filament of from 1 to 15 denier and varying in denier along the filament length is provided; the denier variations of the said filament having a contrast of at least 1.5 and occurring at least 3 times per inch along the filament length. By denier variation is meant that the cross-section of the filament varies regularly between thick and thin along the filament length. In measuring the number of such variations along the filament length, the distance from the thickest portion of the filament to the next thickest portion of the filament or, conversely, from the thinnest portion to the next thinnest portion, is the length of one denier variation. In accordance with this invention, at least 3 such denier variations occur along each inch of the filament length. By the term contrast is meant the ratio of the average denier of thickest portion of the filament to the average denier of the thinnest portion of the filament. Thus, when .the thick portion of the filament has an average denier of 3 and the thinnest portion has an average denier of 1.5, the contrast is 2. .These filaments, when formed into a multi-filament yarn with aligned denier variations among the parallel filaments, are of a low twist crepe variety.

The yarn described above is produced by the use of an apparatus for changing a steady flow of a liquid to a pulsating flow which comprises a conduit for flowing liquid, a piston slidably mounted in the conduit and provided with the passage for the flowing liquid, an annature aflixed to the piston, an electromagnetic driving means for oscillating the armature and piston to transmit pulsations to the liquid flowing through the conduit. This apparatus is located immediately upstream to the spinneret and because of the pulsating flow of the spinning solution, the variable denier yarn described above is formed. The apparatus, while particularly suitable in the formation of the novel filaments of this invention, may be used to produce other variable denier yarns or merely to change a steady flow of liquid to a pulsating flow. The apparatus is hereinafter more fully described by reference to the drawings.

In the accompanying drawings, which illustrate ferred embodiments of the invention:

.pre.

Figure 1 is a longitudinal elevation of one embodiment of the invention in place in the supply line between the conventional supply pump and the spinneret;

Figure 2 is a cross-section taken on line 2-2 of Figure 1;

Figure 3 shows the piston construction of Figure 2 in greater detail;

Figure 4 shows a modified piston insert construction suitable for use in the apparatus of this invention;

Figure 5 shows another modified piston insert construction suitable for use in the apparatus of this invention;

Figure 6 is a cross-section of a longitudinal elevation of another embodiment of the invention in place in the supply line between the conventional supply pump and the spinneret;

Figure 7 is a diagrammatical sketch of the spinning set-up for the variable denier yarns of this invention;

Figure 8 is an illustration of a variable denier, continuous, multi-filament yarn;

Figure 9 is a capacitometer chart showing the denier variation of one of the continuous, multi-filament yarns of this invention.

In Figure 1 spinning liquid is forced by pump 10 through conduit 12 and out of spinneret 14 in the manner understood in the spinning art. The spinneret is mounted on the end of the conduit in a conventional manner as shown in Figure 2. A holder 16-slides onto the pipe end 18 of the conduit, a collar 20 fits insidethe holder and screws onto the end of the pipe, the resilient washer 22 forms a seat thereon for the spinneret, and a surrounding cap 24 screws onto the holder 16 and presses the spinneret against the washer to form a tight seal. Removal of this assembly as a unit is made possible by union 26.

The conduit 12 is surrounded for a portion of its length by a yoke 30 (or magnetic pole pieces) carrying spools 32 and 34 wound with coils of wire 36 and 38, respectively. As shown in Figure 2, the circuits containing the coils and rectifiers 54 and 56 are connected together in parallel with one connecting lead 40 being connected to the fixed tap of a variable transformer 42 andalternating current power line 44. The other side of the transformer is connected to the other power lead, wire 46. The remaining two leads 48 and 50 from the coils. are connected through the oppositely arranged rectifiers to the variable tap 52 of the transformer. Lead 48 from coil 36 runs to the positive side of rectifier 54, the minus side of which is connected to the transformer. Lead 50 from coil 38 runs to the negative side of rectifier 56 and its positive side is connected to the transformer.

The portion of the conduit 12 passing through the yoke 30 is composed of a tube 60 of large diameter surrounding an annular core 62 inside of coil 36 and a similar core 64 inside of coil 38. Core 62 is maintained in position between reducer 66 and washer 68. Core 64 is maintained in position between washer 70 and reducer 72. Between washers 68 and 70 is a movable armature 74 which may comprise a large number of fins extending radially outward. Sliding inside of pipe 18 and core 64, and affixed to armature 74, is a long hollow piston member 76. This member extends all of the way from the spinneret 14 to core 62 at the upstream side of yoke 30. Washer 68 acts as a bearing for the upstream end of the piston. The spinneret end of the piston is enlarged as shown at 78 in Figure 3 to form a bearing inside of pipe 18. With the arrangement shown the liquid flowing through conduit 12 must pass through the inside of the hollow piston on its way to the spinneret 14.

If a liquid of low viscosity is used, a so-called thin liquid, it may be necessary to restrict the size of the exit orifice still further. This may be accomplished in the manner shown in Figure 4 or Figure 5. In Figure 4, a hollow bell-shaped member 80'is press-fitted into the piston at the spinneret end 78 to provide an exit orifice of more restricted size. In Figure 5, a threaded insert 82 is used. By having inserts with orifices of various sizes the apparatus may be adjusted for difierent rates of How and magnitudes of pulsations, as well as difierent liquid yiscosities, by merely changing the insert member 80 or 82. 7

Instead of inserts containing orifices, a rod enlarged like a poppet valve at the end may be used. The stem of the rod would be inserted in a. portion of the piston length-.- At. its enlarged end, the rod could rest against a washer (a modified form of washer 22). The washer and rodwould be constructed' so as to restrict the flow of liquid around the rod. The results on the liquid output would be the same as those achieved by the insertscontaining orifices. p V Another preferred embodiment of the present inventionis that represented by Figure 6. In Figure 6 the spinning liquid is forced by a conventional pump through conduit 12 and out of spinneret 14 in the manner understood in the spinning art. The spinneretis mounted on the end of the conduit as shown in Figure 6.v A front coupling 91, which is securely fastened in the plastic case 97, serves as a securing means for the spinneret.. The head piece 90 is threaded into the front coupling 9I-and the spinneret is fitted over the forward. portion. of this member. The cap 24 is then fitted over the spinneret andthreaded onto the front coupling 91 to hold. the spinneret securely in. place. V The long hollow piston member 76 is threaded at its upstream end 107 and an external butt ringv I02 and a lock ring 101 is securely fastened to said member by means of these threads. Immediately in front of the threaded portion of the long hollow piston member 76. is the spring portion 89 of said member. The spring portion of this member is formed by cutting the long hollow tube in the form of a helix so that the tube itself. acts as its own spring to absorb the shock of the vibrating armature 74' (composed-of a large number of fins extending radially outward) which is afli'xed to the central portion of the hollow piston member 76. At the down.- stream portion of the long hollow piston member is located the piston 78 which is inserted in the. long hollow piston member as is more fully shown in Figure'4'. The long; hollow'piston member 76 is supported and sealed at each endbybearings 93 and104; By'bei'ngso sealed the cooling' (-or in some cases, heating) solution, which enters tube 95 and flows around the fins of the armature 74' and along the hollow piston member 76 to exit tube- 96, not only serves to: cool the whole assembly but also tends to flush any spinning solution which might. seep: through bearings 93 and 10.4. The seal ring 103; serves to. prevent theseepage of. any of the cooling (or; heating) solutiom into. the. long: hollow pistonmember 76-. The armature: 74,, long hollow piston member 76,, and. the annular cores 62. and 64, are completely enclosed by a tube 60 of large diameter. The conduit 12 is surrounded for. a portion of its. length by a yoke 30 carrying spools 32 and S t-wound, with coils '36 and 38'. The tube 60 is so arranged in the plastic case 97 that the coil 38 surrounds the core 64' andcoil 36surrounds-core'62.

The-upstream portion of the supply conduit 12 is secured to the apparatus by means of a flared pipe III: The flared edge of the pipe 'fits securelyagainst a seal ring- 100 to prevent any leakage in the rear assembly; The flared pipe 11 1: is held in placeby an adapter cap 99 whichs'is threadedtontoea; rear coupling 98.. A filter cloth; 108 is mounted. between the. lock. ring: I01; and theseali ring 100: to: filter the spinning v solutionbefore: entersrthez vibratiugrlrollow' piston member.

Materials of high magnetic permeability, such as iron I or cobalt, are employed for yoke 30, cores 62 and '64,

and armature 74. The cores are preferably powdered, and the yoke may be partly hollow to receive powdered iron or the like. The pipes, spinneret, and liquid-conducting parts are generally composed of low permeability materials that also are resistant to attack by the liquid itself, preferably being made of -stainless steel. netic flux path exists through the yoke, core insert, and armature whentheapparamsis operated. Figure 7 represents adiag'rammatical sketch of a typical spinning set-up for producing the variable denier yarns-of the present invention. The spinning solution is supplied by a conventional pump 122 tothe apparatusof themesent invention 123. The apparatus 123 is flushed and cooled. or sometimes heated) by means of a fluid-which is supplied to it through exit. and entrance pipe 120. The power needed to run the 'apparatus'123 is supplied by the electrical lead 121. The spinning solution leaves the apparatus 123 at the spinneret face and enters the coagulating bath'124 which coagulates the spinning solution to form continuous filaments, The filaments are uniformly converged at the convergence point 126 and are then taken by means of a roller arrangement to a conventional-wind-up system 125. Figure 8 is a diagrammatical sketch of one of the variable denier, continuous, multhfilament yarns of the present invention. As is shown by the sketch, the yarnsare composcdof a number of filaments with denier variations which are insubstantial alignment. Figure 9 is a capacitometer chart showing the denier variation of'one ofthe variable denier, continuous, multifilament yarns= of this invention; As shown by the chart for a yarn containing 8 denier variations per inch all of the thick portionsof the yarn have substantially the same denier and, in addition, the narrow portions of the yarn are all of substantially the same denier giving a denier variation which is substantially thesame along the'whol'e fila-mentlength. V

- The mode of operation of the apparatus can be visualizedmost simply as. a superposition of an oscillatory flow of liquid upon a*som e'what' greater steady flow inthe direction. "The normal steady flow is produced bytheaction of'a pump providing liquid under pres sure at the'inl'et end ofthe supply pipe. From here it flows axiallyttoward the spinneret. When the electrical connections are made, the coils alternately receive pulses of current, each one settingup'a figure-eight flux pattern in onehaif'of the respective core, andthe adi'acent' end of the armature, The pulses are provided by the action of the oppositely arranged rectifiers upon the incomingalternating, current 'from the power line or other convenient sources of alternating potential. With the establishment of each field pattern, the. armature moves as close as possible" to the'core' of the coil energized at that instant. Upon cessation of .flux in one coil audits associated core, and consequent initiation of flux in the coil on the other side the armature moves rapidly to minimize the" air gap in the' existing field. The frequency of oscillation of the armature will be identical. with the frequency of the alternating current used to energize the coils. i

As the armature moves back" and forth, the; attached hollow piston oscillates withit, causing an oscillatory fl'ow A mage.,g., viscose rayon, because of the high rate of coagula tion possible in the extruded material, such as viscose; however, it is adaptable also to dry-spinning of fibers such as cellulose acetate or other cellulose derivatives, and to melt-spinning of nylon and other polymeric materials.

The power input required will depend on the viscosity of the liquid to be extruded and the dimensions of the apparatus, particularly the aggregative size of the spinneret orifices. For best results, the cross-sectional area of the most restricted portion of the piston, or the insert 80 (of Figure 4) or 82 (of Figure 5) when inserts are used, will be of the same order of magnitude as the total orifice area of the spinneret, preferably being just slightly larger. The input power can be varied by changing the setting of the transformer. The inserts 80 or 82 are useful in the hollow piston to permit'removal and substitution to match a wide range of spinnerets with the same pulsating piston assembly.

Of course, ordinary power line frequency may prove too low for the high spinning speeds of present textile production. Frequency multipliers of any suitable design, many of which are known to those skilled in the art, may be employed for operation at higher frequencies. Operation as described, when the filamentary material produced is drawn off at constant speed, will result in far more uniform denier variations than usually is accomplished with ordinary mechanical means of forming variable denier yarn. This permits easy processing of the material into regularly patterned crepe type fabrics. On the other hand, if spacing of the denier variations at unequal intervals is desired, this is accomplished easily by frequency switching or scanning with suitable equipment, as will come readily to mind. The apparatus is adapted to operate readily on either regular electrical pulsations such as a conventional alternating current power source, or on random types of electrical pulsations, such as those supplied by the electronic control systems disclosed in U. S. Patents 2,595,220, 2,612,743, and 2,622,282. Average spacing of the denier variations produced will be dependent upon the ratio of the average oscillating frequency and the drawotf speed.

The invention will now be described with respect to regenerated cellulose filaments and yarns. The invention, however, is not restricted thereto but is meant to include variable denier yarns produced from other filament-forming materials such as cellulose nitrate, cellulose acetate, vinyl polymers, acrylics, glass, polyamides, proteins, polyesters, etc.

The apparatus described above under the discussion of Figure 6 is employed using an upstream pressure of 67 pounds per square inch in conduit 12 and a piston speed of 240 cycles per second; 100 cc. of water per minute is run through the apparatus in order to cool and flush it. A viscose solution containing 7% recoverable cellulose and 6% total alkali, calculated sodium hydroxide, is filtered, deaerated, and ripened to a salt index of 4.2 and a viscosity of 39 stokes. The viscose is then extruded through the spinneret 14 (holes 0.003 inch in diameter), into a coagulating and regenerating bath containing, by weight, 11% sulfuric acid, 19.5% sodium sulfate, 0.7% zinc sulfate, and 2.0% glucose. The bath is maintained at a temperature of 55 C. After extrusion the filament is passed over a Y guide which is placed 5 inches from, and directly in front of, the spinneret face. The yarn is then passed for a distance of 40 inches through the bath and up to and around a feed wheel and finally into a rotating bucket. The rotating bucket imparts to the yarn a twist of from about 2 to 4 turns per inch (depending on the spinning speed) and winds the resulting twisted yarn into a cake. A spinning tension of about 011 gram per denier is used in this procedure. The spinning arrangement is shown in Figure 7. The cake is washed, desulfured, finished, dried, and wound into cones in the conventional manner. Table I below gives the characteristics of the yarn produced by this procedure.

TABLE I Variable denier yams Number Spinning Denier, Ex. Denier of filaspeed, Varia- Contrast ments yards/ tiuus/hich per min.

Table H below gives the physical properties of the variable denier yarns produced above.

TABLE II Num- BreakingSt-rength Elongation perber of (g.) cent Twists Ex Denier Filaper ments inch Dry Wet Loop Dry Wet Loop The yarns described above are woven into a plain weave cloth having 96 ends in the warp and 72 ends in the filling. The resulting fabrics have a pleasing crepelike appearance.

The multi-filament yarns which are produced in accordance with the present invention are those composed of the hereinbefore described filaments wherein the denier variations are in substantial alignment. In general these yarns have a total denier of from about 50 to about 400 and are composed of from about 10 to about 400 filaments; each filament having a denier of from about 1 to about 15, a contrast of at least 1.5 and at least 3 denier variations per inch. In the preferred embodiment of the present invention the total denier of the yarn ranges from about 100 to about 200 and is composed of filaments having a denier of from 1 to about 5, a contrast of from 1.5 to about 4 and from 3 to about 9 denier variations per inch.

In producing the variable denier yarns of the present invention there are four basic requirements: (1) Extremely rapid variation in the flow of filament-forming solution through the spinneret; (2) Rapid setting of the filaments as they emerge from the spinneret; (3) Uniform convergence of the filaments so that the variations in denier are not allowed to become out of alignment from filament to filament; and (4) Constant speed draw-off.

As is poined out above the present invention is not restricted to the formation of filaments merely from viscose but includes cellulose acetate, polyamides, polyesters, etc. When using materials other than viscose in the apparatus herein described, simple experimentation will serve to determine optimum operating conditions such as upstream pressure, piston speed, spinning speed, degree of stretch, etc. When using a viscose spinning solution, however, it is preferred to use 0% stretch, from 50 to 100 pounds per square inch upstream pressure, and a spinning speed of from about 50 to about 100 yards per minute. The piston speed is then adjusted to give the desired number of denier variations per inch.

The yarns of this invention, composed of the variable denier filaments, are useful for preparing crepe-like fabrics which are particularly useful in the light-weight fabric wearing apparel field. The usual method of manufacturing fabrics exhibiting crepe-like effects is to weave a fabric consisting wholly or in part of yarns of high twist and to subject the fabrics so obtained to treatment with hot aqueous liquids. The treatment with hot aqueous liquids causes the high twist yarns to shrink and cockle thus imparting to the fabric the characteristic crepe appearance. In the case of fabrics which consist only partially of high twist yarns, the high twist yarns are evenly distributed in the fabric, e. g., the fillling may consist of ly cost ofiproducing the yarn and cause" quently crepe fabrics are relatively expensive. In addi-..

tion, the highly twisted yarn in the fahricmakes the'fabric dimensionally unstable to wetting; arid drying 'andthere fore crepe fabrics .must always befd'ry-cleaned; 'Tne crepe-dike fabrics producedtrom the yarns of the present invention have the advantage of providing a much lower cost fabric, due to the low degree'of twist, and the fabric in addition has dimensional stability, e.--g., it-rnay be laundered rather than dry-cleaned.

I'he fabrics which are produced from the filaments and yarns of the present inventionmay be dyed in the conventional manner and are useful in many difierent types of fabrics. They are particularly usefuI in the fine dress goods field for themaking of blouses, and dresses in direct dyed. fabrics or'printcloths'.

, Many modifications will be apparent to those skilled in the art firom the reading of the above without a departure from the inventive concept v This application is a continuation-impart of the United States application Serial No. 357,171.

. What is claimedis: I I

1. Apparatus for changing a steady flow of liquid to a pulsating flow whichcornpn'ses-a conduit for flowing liquid, a hollow piston slidably mounted'in the conduit as the only moving part, said piston being open at each end and throughout its length to'provide'a continuously open passageway through the piston for the flowing liquid, an armature atfixed to the piston, and electromagnetic driving means for oscillating the armature and piston at high frequency to transmit pulsations to the liquid'fiow ing, through thepiston; a

2.. Apparatus for changing a steady flow of liquidto a pulsating flow whichcomprises a conduit forflowing liquid, a hollow piston slidably mounted in the ,conduit as the only moving part, said pistonheing open at each.

end and throughout itslength to provide a continuously open passageway through the piston for the flowing liquid, anarmature afiixed to the piston, fixed magnetizable coils located on each side of the armature, and electrical means for alternately energizing, the coils to 'oscillate the armature and piston at high frequency to transmit pulsations to'the' liquid flowing; through the piston.

3. Apparatus for spinning artificial'filaments compris- V 8 mg a spinneret, a eojndnit leading tothe-s innereg means for supplying filame'nflforming liquid through the conduit under pressursgahohqw-piston slidably mounted-in the conduit as the only movin'g part, said piston being open" at each end'and'throufghout its" to pravr re a con tinu'ousIy open passage ay hrmiga the piston to the liquid terminating iriihaedia'tely 'adjac erit td spinneret, and 'drivingrneans for' oscill'ating the piston athigh ire quency to-transr'n'it pulsations 'totheliquid' supplied to the spinner'etd 4. Apparatus for spinning-artificial filaments comprising' a spinner'et, a conduit leading to the spinneret, meansfor snpplying filamcnt forinin'g liquid through the con:

duit under pressure, a hollow piston slidably rnountediin the conduit as the only moving part, said piston open at each end-andthrougihout its length, to provide a continuously open passagewaythrough: the piston-for the liquid, an armature aflixed to the piston, fixed inagnetizzt 'blecoils located on eachsidbf the armature, an electrical means for alternately energizingthe coils to oscillate the armature and piston at high frequency' to'trans-f mit pulsations to the liquid supplied to the spinner-ct.

5 Apparatus as defi'ncd'in claim-4 in which the exit of said piston passage is immediately adjacent to said spinneret; j 4 p 6. Apparatus as defined in claim 4 in which the cross: sectional area of the most restricted portion of said piston passage is of the same order of magnitude as the total power of controlled potential and frequency connected to said coils in parallel through oppositely arranged rectifiers. 9. Apparatus of claim 5 which contains a means for cooling and flushing the-said slidably mounted piston an d a filtering means located at the entrance of said piston passage,

References Cited in'th'e file of this patent UNITED STATES PATENTS 2,468,666 Heim Apr. 26, 1949 2,671,929 Gayler Mar. :16, 1954 2,686,955 Luther Aug. 24, 1954 2,750,653- White June 19, 1956 

4. APPARATUS FOR SPINNING ARTIFICIAL FILAMENTS COMPRISING A SPINNERET, A CONDUIT LEADING TO THE SPINNERET, MEANS FOR SUPPLYING FILAMENT-FORMING LIQUID THROUGH THE CONDUIT UNDER PRESSURE, A HOLLOW PISTON SLIDABLY MOUNTED IN THE CONDUIT AS THE ONLY MOVING PART, SAID PISTON BEING OPEN AT EACH END AND THROUGHOUT ITS LENGTH TO PROVIDE A CONTINUOUSLY OPEN PASSAGEWAY THROUGH THE PISTON FOR THE LIQUID, AN ARMATURE AFFIXED TO THE PISTON, FIXED MAGNETIZABLE COILS LOCATED ON EACH SIDE OF THE ARMATURE, AND ELECTRICAL MEANS FOR ALTERNATELY ENERGIZING THE COILS TO OSCILLATE THE ARMATURE AND PISTON AT HIGH FREQUENCY TO TRANSMIT PULSATIONS TO THE LIQUID SUPPLIED TO THE SPINNERET. 